Operating slide for firearms



Jan. 16, 1951 I w. A. scHAlcH Patented Jan. 16, 1951 UNITED sTATEsPATENT oFFicE- 2,538,048 OPERATING S LIDE FOR FIREARMS Wilbur A.Schaich, Highland Park, Mich.

Application November 10, 1948, Serial No. 59,325

3 Claims. (Cl. 89-129) (Granted under the act of March 3, 1883,' as

amended April 30, 192'8; 370 O. G. 757) The invention described hereinmay be manufactured and used by or for the Government for governmentalpurposes without payment of any royalty thereon.

- This invention relates to an improvementI in firearms, moreparticularly to improving the timed opening of an automatic firearmbolt.

In many firearms of the automatic or semiautomatic type the timing ofthe action is such that the breech closure member or bolt opens underrelatively high residual breech pressure. Opening under such a conditionadversely affects the firearm by producing excessive forces on therecoiling parts, harder extraction of the fired case due to its expandedcondition and hence greater possibility of fracture of the extractor andthe moving components of the action.

This condition is commonly found in the U. S. carbine, caliber v.30, M1wherein the gas utilized to actuate the Operating slide of such firearmis tapped from the barrel at a point quite near the chamber hence wherethe breech pressure is exceedingly high. The tappet type actuation ofthe Operating slide coupled with a short dwell travel of such slidebefore Contacting the bolt lug cam results in the repeated unlocking ofthe bolt or breech member before the Chamber pressure has dropped to theproper level for safe opening of the firearm bolt. i

Various modifications have heretofore been utilized in order to delaythe opening of the bolt of the above mentioned firearm. One of such'modifications was to increase the dwell portion of the Operating camcontained in the bolt handle of the inertia slide and another was toincrease the weight of the inertia slide. Neither of these modicationssatisfactorily accomplished the desired end. Increasing the weight ofthe Operating slide, while slightly delaying the opening of the firarmbolt, added materially to the weight of the firearm. Increasing thedwell portion of the Operating cam proved unsatisfactory and impracticaldue to design limitations required to maintain interchangeability.

Accordingly, it is an object of this invention to provide an improvedfirearm of the gas operated, automatic type characterized by the delayedunlocking of the bolt member to insure that the breech pressure hasdropped to a safe level.

A further object of this invention is to provide means whereby the dwellperiod of an Operating slide of a firearm may be readily increasedwithout major redesign of such firearm to delay unlooking of the firearmbolt until a desirably low and safe breech pressure is reached.

A particular object of this invention is to pro- Vide an improvedinertia slide for an automatic firearm of the type similar to the U. S.carbine, caliber .30, M1, whereby improved timing of the opening of thebolt is achieved.

The specific nature of the invention as -well as other objects andadvantages thereof will clearly appear from the following description ofa preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a'fragmentary top elevational view of the receiver end of afirearm embodying this invention, showing the battery position of theimproved inertia member and also the recoil positionlof such member indotted outline.

Fig. 2 is a fragmentary side elevational view of the firearm of Fig. lshown with the stock removed to better illustrate the improved inertiaslide.

Fig. 3 is a longitudinal sectional view taken along the line 3-3 ofFig'. 2.

In Figs. 1 and 2 there is shown a firearm embodying this invention.While not limited thereto, this invention is shown as embodied in a gasoperated, automatic firearm of the type known as the U. S. carbine,caliber .30, M1. Such a specific example is merely chosen for purposesof illustration, as obviously this invention can be applied to any gasoperated firearm having a reciprocating Operating slide or breechactuating member. The firearm shown in such figures comprises mainly areceiver I, a barrel 2, an Operating slide 3 and a stock 4 housing suchmembers.

Barrel 2 is Secured to receiver I and operating slide 3 is mounted onbarrel 2 for longitudinal reciprocal movement in the usual manner.However, slide 3 is formed in two pieces, a substantially rectangularshank portion lll, and ahandle portion 5.

Such handle portion 5 Vtelescopes into a hollow bar-like member 6projecting rearwardly from inertia portion IG and integrally formedtherewith, as will be presently described. A plunger 'I surrounded by aspring |5 is provided to bias slide 3 forwardly to battery position. Thefor- Ward end of plunger 'l abuts the rear surface of portion [4 whilethe other end of spring biased plunger l is contained within a suitablerecess provided in receiver I. Handle portion 5 provides the usualOperating connection to a bolt 8 slidably contained within receiver l. Abolt lug (not shown) engages a suitable cam slot in the inside face ofhandleV portion 5, likewise not shown.

Handle portion 5 is provided with a forwardly projecting integralbar-like end l0 which is Each end of pin [3 is preferably peened, as,

shown in Fig. 3, to permanently secure such pin in bar 6. When Operatingslide 'is inv it'sbattery' position on the firearm, as shown inFigs. 1and2, the portion 14 is effectively separated from handle 5 by virtue Ofslot ll. separation is here shown as limited to approximately One-halfinch, although greater or lesser separation may be easily attained' bylengthem'ng.

or decreasing the length Of slot I l. Spring biased plunger 1 maintainsthe two parts of the operating. slide in such. separated position untildischarge of a cartridge as will be presently described.

When a cartridge is fired in the firearm. the actuating gases impinge ona gasactuating mechanismL (not shown) which. in turn imparts-arearwardblow to slide 3, thereby driving such slide rapidly rearwardly. Theportion lll of slide 3 travels a substantial distance, bar portiontelescoping into recess 9 of bar 6. before the rear end4 Of bar 6-effectively. engages handle portion by striking. shoulder. Illa.

Upto the. time such impactoccurs; nO-unlocking. movement of the. handleportion 5 of bolt 8' has taken place. In Other words, the: bolt 8: issecurely looked to the receiver I- duringthe initial rearward travellofinertia portion 14 of .the.slide= Obviously this introduces; a4substantial delaythereby providing more time for reduction of. pressureVin the barrel..

When the rear end of bar. 6 strikeshandle portion 5, such handle ismoved rearwardly, thereby adding the usual time delay or dwellperiodincorporated in the unlocking cam (not shown) to that,- obtainedby telescoping the. inertia. slide. Atlthe termination of thesecondarydwell movement of the handle portion 5, the looking lug of the bolt (notshown). is rotated by thev cam; slotv (not. shown) contained in thehandle portion: 5tO effect unlocking of such bolt from receiver. L Dueto the momentum Of inertia=slide 3v andV to residual gas pressure in=the chamber, bolt 8 is driven rearwardly to4 its recoil positionas shownin dotted Outline in Fig. l.

From; theforegoing description itis thus seen that an. added. time lagOr dwelly period is introduced, prior to Opening of the firearm: bolt bymeansof the telescoping Operating slide providedby this invention. Thetime lag between firing ofthecartridge and unlocking ofthe/bolt-so-introduced. plus. the. normal dwell, period of.. theunlocking cam of the Operating slide. provides ample. time for loweringof the breechpressure to. alevel. permitting safe: opening of the bolt.

The. amount of such.

When the bolt is unlocked under relatively low chamber pressure thefired cartridge case is easily extracted and the recoil forces acting onthe receiver and moving parts are greatly reduced. It is further desiredto point out that the means provided by this invention for achieving anyadditional time lag or dwell period to improve the timing of the openingof the firearmf bolt, is achieved in a simple manner which isinexpensive to: manufacture and easy to produce, does not requiremodificaton of the major components of the firearm; and may beinterchangeably applied to existingfirearms merely by substitution ofthe Operating slide. Furthermore, the telescoping 'two part Operatingvslide does not impair the manual operation of the Operating slide.

I claim:

1:. In an: automatic' firearm with a reciprocable bolt-and a gasOperating mechanism, an Operating slide having two parts, a first partserving as an inertia device andv engagingthe gas Operating mechanismandasecond part engaging the bolt; and time. delay means connecting the'twolparts; said time delay means comprising. a-rod-'-like:eir-VtensionLL on one part carrying an inclosed rectangular slot, a pinrigidly se'curedl tO- the: other: part engagingthe slot; and? recessedmeanssirr'the said'other part slideably receiving'therOd.-like'.extension and thereby4 permittingf limited telescopic motionof the Operating slidel when the. inertia part is actuated.

2. A two part operatingtslide for azgasfoperated firearm With areciprocable' bolt comprisin'gf.y a: forward shank part servingi as:aninertia device;v a rearwardv handle part; and: time delay-1 means'connecting the forward .and rearward partsf and preventing prematureVaction of the handle. part; said time delay means compri'singi a=rod-likefextension Onthe handlepart'carrying: arr inclosed rectangul'arslot, a pin-'rigidl'y securedtoftheshank' part engagingv the slot, anda.bore in' the shank part slideably receiving the rod-likeI extensionandthereby permitting' limited' telescopi'c" motion? of' the Operatingslide when' the in'ertiaA part'is actuated.

3. An Operating slide.- as in cliaim 2 inwhich' the pin of the timedelay means extends tfrans versely through the rectangularsslot*andlrtr-avel longitudinally thereifn.

WILBUR SCHIA'ICHI REFERENCES CITED- Thev following references are ofrecordA in'V the file of this* patent:

UNITED STATES PATENTS.

Number Name Date:

577,485 Maxim'- Feb-23; '18974 70.9;880 Knight' Sept. 30, 1902 799,884'Augezd Sept;,19;'1905 2356,,595 Koucky Aug; 22;- 1944' 2,45l',624 Loomiset al, Oct2.-19,.I94'8

